Liquid metal ion source

Patent metadata

Field	Value
Publication number	US-11170967-B2
Application number	US-202016824069-A
Country	US
Kind code	B2
Filing date	Mar 19, 2020
Priority date	Mar 22, 2019
Publication date	Nov 9, 2021
Grant date	Nov 9, 2021

Abstract

An ion source is configured to form an ion beam and has an arc chamber enclosing an arc chamber environment. A reservoir apparatus can be configured as a repeller and provides a liquid metal to the arc chamber environment. A biasing power supply electrically biases the reservoir apparatus with respect to the arc chamber to vaporize the liquid metal to form a plasma in the arc chamber environment. The reservoir apparatus has a cup and cap defining a reservoir environment for the liquid metal that is fluidly coupled to the arc chamber environment by holes in the cap. Features extend from the cup into the reservoir and contact the liquid metal to feed the liquid metal toward the arc chamber environment by capillary action. A structure, surface area, roughness, and material modifies the capillary action. The feature can be an annular ring, rod, or tube extending into the liquid metal.

First claim

The invention claimed is:

1. An ion source configured to form an ion beam, the ion source comprising:
an arc chamber generally enclosing an arc chamber environment;
a reservoir apparatus configured to provide a liquid metal to the arc chamber environment, wherein the reservoir apparatus comprises:
a cup having a recess configured to generally contain the liquid metal therein; and
a cap, wherein the cap is in selective engagement with the cup and generally encloses a top portion of the reservoir apparatus, therein defining a reservoir environment associated with the liquid metal, and wherein the cap further comprises one or more features extending into the recess, wherein the one or more features are configured to contact the liquid metal within the recess and to feed the liquid metal toward the arc chamber environment via capillary action; and

a biasing power supply configured to electrically bias the reservoir apparatus with respect to the arc chamber.

2. The ion source of claim 1 , wherein the cup is configured to generally contain the liquid metal therein by gravity.

3. The ion source of claim 1 , wherein the liquid metal resides in the reservoir environment, and wherein the reservoir apparatus is further configured to selectively evaporate at least a portion of the liquid metal therein.

4. The ion source of claim 3 , wherein the reservoir apparatus is configured to selectively evaporate the at least a portion of the liquid metal by a selective heating of the reservoir apparatus via a heat source.

5. The ion source of claim 4 , wherein the heat source comprises one or more of a plasma generated within the arc chamber, an energy associated with ions from the plasma striking the reservoir apparatus, and an auxiliary heater.

6. The ion source of claim 1 , wherein the cap comprises one or more holes defined therein, wherein the one or more holes provide fluid communication between the reservoir environment and the arc chamber environment.

7. The ion source of claim 1 , wherein the one or more features comprise one or more of a predetermined surface area, surface roughness, and surface material configured to provide the capillary action.

8. The ion source of claim 1 , wherein the one or more features comprise one or more of an annular feature extending from the cap into the recess, a reservoir feature extending from the recess toward the cap, and an elongate feature extending from a central portion of the cap into the liquid metal within the recess.

9. The ion source of claim 1 , wherein the liquid metal is comprised of one of aluminum, gallium, and indium.

10. An arc chamber for forming an ion beam, the arc chamber comprising:
a housing generally enclosing an arc chamber environment;
a reservoir apparatus positioned within the arc chamber environment, wherein the reservoir apparatus is configured to contain a liquid metal in the arc chamber environment, wherein the reservoir apparatus comprises a cup and a cap, wherein the cup has a recess configured to at least partially contain the liquid metal therein, and wherein the cap is in selective engagement with the cup and generally encloses a top portion of the reservoir apparatus, therein defining a reservoir environment associated with the liquid metal, wherein the liquid metal resides in the reservoir environment, and wherein the reservoir apparatus is further configured to selectively evaporate at least a portion of the liquid metal therein, wherein the cap comprises one or more features extending into the cup, wherein the one or more features are configured to contact the liquid metal within the recess and to feed the liquid metal toward the arc chamber environment via capillary action; and
a biasing power supply configured to electrically bias the reservoir apparatus and to form a plasma within the arc chamber environment.

11. The arc chamber of claim 10 , wherein the reservoir apparatus is configured to selectively evaporate the at least a portion of the liquid metal by a selective heating of the reservoir apparatus via a heat source, wherein the heat source comprises one or more of the plasma generated within the arc chamber, an energy associated with the ion beam, and an auxiliary heater.

12. The arc chamber of claim 11 , wherein the cap comprises one or more holes therein, wherein the one or more holes provide fluid communication between the reservoir environment and the arc chamber environment, and wherein the one or more holes have one or more diameters, and wherein the one or more holes are oriented such that the plasma in the arc chamber does not have direct contact with the liquid metal in the recess.

13. The arc chamber of claim 10 , wherein the one or more features comprise an annular ring defined in the cap, wherein the annular ring extends from a main portion of the cap into the liquid metal within the recess.

14. The arc chamber of claim 10 , wherein the one or more features comprise an elongate feature extending from a main portion of the cap into the liquid metal within the recess.

15. The arc chamber of claim 10 , wherein the cap comprises one or more holes therein, wherein the one or more holes provide fluid communication between the reservoir environment and the arc chamber environment, and wherein the one or more holes have one or more diameters, and wherein the one or more holes are oriented such that the plasma in the arc chamber does not have direct contact with the liquid metal in the recess.

16. An arc chamber for forming an ion beam, the arc chamber comprising:
a housing generally enclosing an arc chamber environment;
a reservoir apparatus configured to contain a liquid metal in the arc chamber environment, wherein the reservoir apparatus comprises:
a cup having a recess configured to at least partially contain the liquid metal therein;
a cap in selective engagement with the cup and generally enclosing a top portion of the reservoir apparatus; and
one or more features associated with one or more of cup and cap and configured to contact the liquid metal within the recess and to feed the liquid metal toward the arc chamber environment via capillary action; and

a biasing power supply configured to electrically bias the reservoir apparatus and to form a plasma within the arc chamber environment.

17. The arc chamber of claim 16 , wherein the one or more features comprise one or more of an elongate feature and an annular ring, wherein the elongate feature extends from a main portion of the cap into the liquid metal within the recess, and wherein the annular ring is defined in the cap, wherein the annular ring extends from a main portion of the cap into the liquid metal within the recess.

18. The arc chamber of claim 16 , wherein the one or more features comprise one or more of a predetermined surface area, surface roughness, and surface material configured to provide the capillary action.

19. The arc chamber of claim 16 , wherein the one or more features comprise one or more of an annular feature extending from the cap into the recess, a reservoir feature extending from the recess toward the cap, and an elongate feature extending from a central portion of the cap into the liquid metal within the recess.

20. The arc chamber of claim 16 , wherein the cap comprises one or more holes defined therein, wherein the one or more holes provide fluid communication between a reservoir environment associated with the cup and the arc chamber environment.

Assignees

• Axcelis Tech Inc

Inventors

• Bassom Neil
• Colvin Neil
• Hsieh Tseh-Jen
• Ameen Michael

Classifications

• H01J2237/0805

  Liquid metal sources · CPC title

• H01J37/3171

  for ion implantation · CPC title

• H01J37/08 Primary

  Ion sources; Ion guns · CPC title

• H01J27/08

  using arc discharge · CPC title

• H01J2237/08

  Ion sources · CPC title